TOTAL PROMPT FISSION NEUTRON SPECTRUM FROM THERMAL NEUTRON-INDUCED FISSION OF U-233 AND Pu-239

Authors & Affiliations

Vorobyev A.S., Shcherbakov O.A.
B.P Konstantinov Petersburg Nuclear Physics Insitute, NRC “Kurchatov Institute”, Gatchina, Russia

Vorobyev A.S. - head of the group FDYA THEY, Dr. Sci.(Phys.-Math.) NRC “Kurchatov Institute” B.P Konstantinov Petersburg Nuclear Physics Insitute. Contacts: PNPI, Orlova Roscha, Gatchina, Leningrad district, Russia, 188300. Tel.: +7 (813) 714-64-44, e-mail This email address is being protected from spambots. You need JavaScript enabled to view it..
Shcherbakov O.A. - Senior Researcher, Dr. Sci.(Phys.-Math.) NRC “Kurchatov Institute” B.P Konstantinov Petersburg Nuclear Physics Insitute.

Abstract

The prompt fission neutron spectra from thermal neutron - induced fission of ²³³U, ²³⁹Pu and spontaneous fission of ²⁵²Cf have been measured under the equal experimental conditions at the PNPI research reactor (Gatchina). During the measurements, the identity of the experimental geometry and subsequent analysis of the data obtained for these two investigated nuclei was guaranteed by the construction of the experimental set-up and data processing procedure. The measurements were performed simultaneously for the 11 values of angle between neutron emission direction and the light fission fragment direction of motion. To select fission fragment direction, the multi-wire proportional counters were used. The prompt fission neutron energy was obtained by the time-of-flight method. The pulse shape analysis was additionally used for separation of neutron and γ-quanta events. As a result of the data analysis performed, the ratios of the total prompt fission neutron spectrum of ²³³U(n,f) and ²³⁹Pu(n,f) to the total prompt fission neutron spectrum of ²⁵²Cf(sf) have been obtained. The obtained ratios have a weak dependence on the features of the experimental set-up and are free from errors inherent to absolute measurements. By using these ratios, the total prompt fission neutron spectra of ²³⁵U(n,f) and ²³⁹Pu(n,f) were calculated using the total prompt fission neutron spectrum of ²⁵²Cf(sf) recommended as an international standard for neutron spectra measurement.

Keywords
nuclear fission, ²³⁵U, ²³⁹Pu, thermal neutrons, total prompt fission neutron spectra

Article Text (PDF)

References

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UDC 539.173

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2016, issue 2, 2:4

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TOTAL PROMPT FISSION NEUTRON SPECTRUM FROM THERMAL NEUTRON-INDUCED FISSION OF U-233 AND Pu-239